1. Field of the Invention
The present invention generally relates to controlling small payload air vehicles in flight, and more particularly, to automatically controlling Unmanned Air Vehicles (UAVs) and Remotely Piloted Vehicles (RPVs) to sense and avoid potential collisions with other local air vehicles.
2. Background Description
Currently, Unmanned Air Vehicles (UAVs) and/or Remotely Piloted Vehicles (RPVs) are accompanied by a manned “chaperone” aircraft to mitigate risk of collision when operating in National Air Space (NAS). A chaperone is particularly necessary to assure that the aircraft (UAV or RPV) does not collide with other manned or unmanned aircraft operating in the vicinity or vice versa. Unfortunately, chaperoning such a vehicle is labor intensive and not particularly useful, other than for test and demonstration purposes.
Manned aircraft rely on air traffic control, transponders, and pilot vision for collision avoidance. While transponders are required on all commercial aircraft, many private aircraft do not carry transponders, and transponders may not be utilized in combat situations. Further, there have been cases of air traffic control issuing commands that contradict transponder avoidance recommendations. For manned aircraft, the human pilot visually identifies local moving objects and makes a judgment call as to whether each object poses a collision threat. Consequently, vision based detection is necessary and often critical in detecting other aircraft in the local vicinity.
Currently, the Federal Aviation Administration (FAA) is seeking an “equivalent level of safety” compared to existing manned aircraft for operating such aircraft in the NAS. While airspace could be restricted around UAVs or UAVs could be limited to restricted airspace to eliminate the possibility of other aircraft posing a collision risk, this limits the range of missions and conditions under which an unmanned aircraft can be employed. So, an unaccompanied UAV must also have some capability to detect and avoid any nearby aircraft. An unmanned air vehicle may be equipped to provide a live video feed from the aircraft (i.e., a video camera relaying a view from the “cockpit”) to the ground-based pilot that remotely pilots the vehicle in congested airspace. Unfortunately, remotely piloting vehicles with onboard imaging capabilities requires both additional transmission capability for both the video and control, sufficient bandwidth for both transmissions, and a human pilot continuously in the loop. Consequently, equipping and remotely piloting such a vehicle is costly. Additionally, with a remotely piloted vehicle there is an added delay both in the video feed from the vehicle to when it is viewable/viewed and in the remote control mechanism (i.e., between when the pilot makes course corrections and when the vehicle changes course). So, such remote imaging, while useful for ordinary flying, is not useful for timely threat detection and avoidance.
Thus, there is a need for a small, compact, lightweight, real-time, on-board collision sense and avoidance system with a minimal footprint, especially for unmanned vehicles, that can detect and avoid collisions with other local airborne targets. Further, there is a need for such a collision sense and avoidance system that can determine the severity of threats from other local airborne objects under any flight conditions and also determine an appropriate avoidance maneuver.